Now you can add some egg. you don’t have to, but without egg it’s more crumbly and less cake-y. You can do a whole egg, but I like to break the egg into a ramekin and stir it up, then split it between two cups of coffee cake, or just use half for one coffee cake. But really, play it by ear. Try it out and see what tastes best to you.

Then stir in 2 tablespoons of sour cream and a few drops of vanilla. We’re talking droplets here, don’t add too much.

Stir in 1/4 cup of flour and 1/8 teaspoon baking powder.

If you want some crumb topping (you know you do), in a separate ramekin or bowl add 1 tablespoon butter, 2 tablespoons flour, 1 tablespoon of brown sugar, and 1 teaspoon of cinnamon.

Smoosh it together with your fingers for a few.

Now back to your cup. Your ingredients are all mixed up, so…

Add the crumb topping mixture to the cup…

Then microwave it. Start with 1 minute, then do 10 seconds more until it’s done to your liking. For my microwave, a minute 20 seconds does it perfectly.